Technique for effectively utilizing limited bandwidth of a communications network to deliver programming content

ABSTRACT

To effectively utilize the bandwidth of a cable TV network, which is limited, analog TV program material is digitized and compressed before its transmission over the network. The resulting signals consume only part of the analog TV band traditionally needed for transmission of the analog TV program material. The newly available bandwidth in the analog TV band may be utilized for other cable TV services, e.g., video-on-demand (VOD) services. A reception gateway is employed at a user location to frequency-translate any VOD signals, transmitted through the analog TV band, to another frequency band, thereby avoiding disturbing the normal operation of a set-top terminal in receiving the analog TV program material through the analog TV band at the user location.

RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 10/983,378 filed Nov. 8, 2004 which is hereby expresslyincorporated by reference in its entirety and which claims under 35U.S.C. § 119(e) the benefit of Provisional Application No. 60/526,621filed on Dec. 3, 2003.

FIELD OF THE INVENTION

The invention relates to communications systems and methods, and moreparticularly to a system and method for delivering programming materialto subscribers via a communications network, e.g., cable televisionnetwork.

BACKGROUND OF THE INVENTION

In many existing cable systems, cable operators provide programmingmaterial in more than one format. For instance, certain broadcast TVprograms may be provided in an analog format, e.g., in accordance withthe standards of the National Television System Committee (NTSC). Otherbroadcast TV programs may be provided in a digital format. One commondigital format is the well-known Moving Pictures Experts Group 2(MPEG-2) format. The MPEG-2 format effects a compression of video andaudio data to allow multiple programs, with different video and audiofeeds, to be multiplexed into a transport stream traversing a singletransmission channel, as opposed to one program per transmission channelin analog TV. A set-top terminal (STT) at the user premises may be usedto decode an MPEG-2 encoded transport stream, and extract the desiredprogramming material therefrom.

MPEG-2 Background

In accordance with the MPEG-2 standard, video and audio data associatedwith a given program is compressed, and carried in the form of packetswithin a packetized elementary stream (PES). For digital broadcasting,one or more programs and their associated PESs may be multiplexed into asingle transport stream. A transport stream has PES packets furthersubdivided into short fixed-size data packets, which carry encoded videoand audio data associated with one or more programs. A transport streamcomprises not only a multiplex of audio and video PESs, but also otherdata such as MPEG-2 metadata describing the transport stream. The MPEG-2metadata includes a program associated table (PAT) that lists everyprogram in the transport stream. Each entry in the PAT points to aprogram map table (PMT) that lists the elementary streams making up eachprogram.

The aforementioned fixed-size data packets in a transport stream eachcarry a packet identifier (PID) code. Packets in the same elementarystreams all have the same PID, so that a decoder can select theelementary stream(s) it needs and reject the remainder.Packet-continuity counts are implemented to ensure that every packetthat is needed to decode a stream is received.

In prior art, analog TV signals, compared with digital TV signals,utilize a relatively large amount of network bandwidth for transmissionof the same program material. In many conventional cable systems, a 6MHz transmission channel may be utilized to transmit a single analogprogram. In contrast, with the use of a digital compression technique,e.g., the MPEG-2 technique, a 6 MHz transmission channel may accommodatenine or more digital programs at the same time.

SUMMARY OF THE INVENTION

As the number of program channels, and use of on-demand services such asmovies-on-demand, subscription VOD services are ever increasing, thecable TV network is constantly strained for additional bandwidth todeliver program channel material and services. The invention is directedto effectively utilizing the limited network bandwidth to meet suchincreasing needs.

In accordance with the invention, analog signals representingprogramming material (e.g., analog TV programming material) received bythe cable operator are digitized, and compressed before theirtransmission over the network, to conserve network bandwidth.Advantageously, some of the bandwidth which would otherwise be neededfor analog TV broadcast can be made available for other services, suchas the VOD services. The resulting digital signals representing theanalog TV programming material are transmitted through a first subbandin a first frequency band (e.g., the traditional analog TV band) of thecommunications network. Selected signals (e.g., containing VODprogramming material) are transmitted through a second subband in thesame analog TV band of the communications network. The first subband andsecond subband are exclusive of each other.

However, an STT at a user location is programmed to tune to the analogTV band to obtain the analog TV programming material. Thus, withoutdisturbing the normal operation of the STT, in accordance with theinvention, a reception gateway which may be installed at the userlocation, converts the digitized, compressed analog TV programmingmaterial to its original analog form, which reoccupies the analog TVband at the user location. In anticipation of the band reoccupation, thereception gateway frequency-translates the selected signals to a secondfrequency band outside the analog TV band. As a result, by using thereception gateway at the user location in accordance with the invention,the digitization and compression of analog TV programming material inthe headend, and use of the analog TV band for transmission of VODprogramming material are transparent to the STT.

BRIEF DESCRIPTION OF THE DRAWINGS

Further objects, features and advantages of the invention will becomeapparent from the following detailed description taken in conjunctionwith the accompanying drawing showing illustrative embodiments of theinvention, in which:

FIG. 1 illustrates an allocation of frequency bands for transmission ofdifferent types of programming material in a prior art cable TV system;

FIG. 2 illustrates a broadband communications system, in accordance withan embodiment of the invention;

FIG. 3 illustrates components of an analog signal processor in thesystem of FIG. 2;

FIG. 4 illustrates a format of a request for a VOD program sent from aset-top terminal (STT) to a headend in the system of FIG. 2;

FIG. 5 illustrates an allocation of frequency bands for transmission ofprogramming material in the system of FIG. 2;

FIG. 6 is a flowchart depicting a routine for utilizing availablebandwidth in a frequency band for non-VOD services in prior art toprovide VOD services, in accordance with an embodiment of the invention;

FIG. 7 illustrates a resource table that may be maintained by a resourcemanager, in accordance with an embodiment of the invention;

FIG. 8A illustrates a transmission channel for transmitting a VODtransport stream in the prior art frequency band for non-VOD services,in accordance with an embodiment of the invention;

FIG. 8B illustrates a frequency subband to which the VOD transportstream is frequency-translated at a user location, in accordance with anembodiment of the invention;

FIG. 9 is a block diagram of a reception gateway for performing, amongothers, the frequency translation of the VOD transport stream at theuser location, in accordance with an embodiment of the invention; and

FIG. 10 is a flowchart depicting a routine for the STT to receive therequested VOD program contained in the VOD transport stream.

DETAILED DESCRIPTION

In a prior art cable TV system, programming material for various programchannels, whether in an analog or a digital format, is transmitted overa multi-channel delivery network, e.g., cable TV network, comprising oneor more transmission channels. The terms “transmission channel” and“program channel” used here should not be confused. A “transmissionchannel” signifies a designated frequency band through which a transportstream containing program material and/or data is transmitted. Atransmission channel may comprise, e.g., a 6 MHz frequency band. A“program channel” signifies the source of programming material or theservice for a user's consumption. For example, a user may select programchannel 2 to view programming material provided by CBS, program channel14 to view programming material provided by ESPN, etc.

In the prior art, analog program channel material is transmitted viatransmission channels within a first designated frequency band, whiledigital program channel material is transmitted via transmissionchannels within a second designated frequency band. For example,referring to FIG. 1, a cable operator may transmit analog programchannel material via transmission channels populating analog TV band103, which ranges from, say, 150 MHz to 550 MHz, and digital programchannel material via transmission channels populating digital TV band105, which ranges from, say, 550 MHz to 650 MHz. In addition, some cableoperators may designate a third frequency band for transmittingnon-broadcast services such as video-on-demand (VOD) services. Suchservices are typically provided in digital form. In this example, acable operator may deliver VOD programming material via transmissionchannels populating digital on-demand (DOD) band 107, which ranges from,say, 650 MHz to 750 MHz.

As the number of program channels, and use of on-demand services such asmovies-on-demand, subscription VOD services are ever increasing, thecable TV network is constantly strained for additional bandwidth todeliver program channel material and services. The invention is directedto effectively utilizing the limited network bandwidth to meet suchincreasing needs. In accordance with the invention, the analog programchannel material received by the cable operator is digitized, andcompressed, e.g., pursuant to the well known MPEG-2 technique, beforeits transmission over the network, to conserve network bandwidth.Advantageously, some of the bandwidth which would otherwise be neededfor analog TV broadcast can be made available for other services, suchas the VOD services.

However, an STT at a user location is programmed to tune to analog TVband 103 to obtain different analog program channel materials. Thus,without disturbing the normal operation of the STT, in accordance withthe invention, a reception gateway which may be installed at the userlocation, converts the digitized, compressed analog program channelmaterial to its original analog form, which reoccupies analog TV band103 at the user location. In anticipation of such band reoccupation, thereception gateway frequency-translates any non-analog TV program streamscontaining, e.g., VOD programs, transmitted within analog TV band 103,to another band at the user location (e.g., DOD band 107). As a result,by using the reception gateway at the user location in accordance withthe invention, the digitization and compression of analog programchannel material in the headend, and use of the analog TV band fortransmission of VOD programs are transparent to the STT. That is, as faras the STT is concerned, different types of program are transmittedaccording to the prior art frequency band allocation, as illustrated inFIG. 1.

FIG. 2 illustrates broadband communications system 100, e.g., a cable TVsystem, embodying the principles of the invention. Headend 105 receives,among others, programming materials attributed to various programchannels, and provides TV broadcast and other services, e.g., VODservices, to users at different user locations, including user locations158-1 through 158-L in a neighborhood connected by the same service areanode 105, where L represents an integer.

The programming materials are delivered from headend 105 to userlocations 158 through “in-band” transmission channels provided by hybridfiber coaxial (HFC) cable network 140. These transmission channels maycomprise 6 MHz bands allocated for downstream communications of theprogramming materials from headend 105 to user locations 158. Quadratureamplitude modulation (QAM) modulator bank 168 in hub 120 modulates thedownstream communications onto selected in-band transmission channels inaccordance with a well known QAM scheme.

One or more service area nodes (e.g., 150) function as interfacesbetween user locations and network 140. At a user location, theaforementioned reception gateway is connected to one or more STTs. Forexample, user location 158-1, which may be a home, includes gateway 675which may be installed inside or outside the home, and is connected toSTT 676.

In addition to the in-band channels, data may be communicated downstreamfrom headend 105 to user locations 158 via one or more forward datachannels (FDCs). FDCs, sometimes referred to as “out-of-band” channels,typically are used to transport data, e.g., system messages, to userlocations 158. In one embodiment, the FDCs may populate the 70-130 MHzband of a coaxial cable. Quaternary phase-shift keying (QPSK) modem pool169 in hub 120 modulates downstream data onto selected FDCs inaccordance with a well known QPSK scheme.

Data may be transmitted upstream from user locations 158 to headend 105via one or more reverse data channels (RDCs), which populate a reversepassband, e.g., 5-40 MHz band, of a coaxial cable. Data carried in theRDCs is modulated in accordance with the QPSK scheme. QPSK modem pool169 in hub 120 receives the QPSK signals in the RDC and performs anynecessary demodulation before transmitting the signals to headend 105.

An STT at a user location may utilize an RDC for sending data including,e.g., user data, messages, etc., to headend 105. Using acontention-based access mechanism established by the Digital AudioVisual Council (DAVIC), a standard setting organization, each STT canshare an RDC with other STTs in the network. This mechanism enables anSTT to transmit upstream messages without a dedicated connection to aQPSK demodulator. The mechanism also provides equal access to the STTsthat share the RDC, and enables detection and recovery from reverse pathcollisions that occur when two or more of the STTs transmit an upstreammessage simultaneously. As also specified by DAVIC, for communicationspurposes, network controller 125, and STTs, are individually identifiedby unique Internet protocol (IP) addresses assigned thereto. In thisinstance, e.g., STT 676 and gateway 675 may each be identified by an IPaddress. However, these IP addresses may be randomly assigned each timethe broadband communication system is reconfigured. As a result, the IPaddress of an STT or that of a gateway or network controller 125 maychange after a system reconfiguration. Nevertheless, network controller125, an STT and a gateway in this instance are also assigned mediaaccess control (MAC) addresses on a permanent basis, surviving anysystem reconfiguration.

In this illustration, headend 105 includes digital TV program receiver109, analog TV program receiver 110, analog signal processor 111,video-on-demand (VOD) server 119, network controller 125, switching unit117, and resource manager 166. In a well-known manner, digital TVprogram receiver 109 receives TV programming material in digital format,e.g., an MPEG-2 format, from one or more digital program channelsources. Receiver 109 then provides to switching unit 117 the digital TVprogram streams, which may have been multiplexed to form one or moredigital TV transport streams. Each transport stream may be identified bya unique transport stream identification (TSID). Each TV program streamwithin a transport stream may be identified by a program stream ID(PID).

Analog TV program receiver 110 receives traditional analog TVprogramming material from one or more analog program channel sources.For example, in prior art, programming material from sixty analogprogram channels may require about 400 MHz bandwidth to convey the same.In accordance with the invention, such required bandwidth is reduced,e.g., to about 40 MHz, by digitizing and compressing the analog TVprogramming material. To that end, the received analog programmingmaterial is fed to analog signal processor 111 wherein, referring toFIG. 3, analog-to-digital (A/D) converter 215 digitizes the analogmaterial in a conventional manner. The digitized analog TV programmingmaterial is encoded using MPEG-2 encoder 220 to effect data-compressionthereof. The resulting MPEG-2 program streams containing the analogmaterial may be encrypted in accordance with a conventional dataencryption scheme to secure the programming content. The output ofanalog signal processor 111, hereinafter referred to as “digitizedanalog TV transport streams,” is fed to switching unit 117.

Video-on-Demand (VOD) server 119, under the control of networkcontroller 125, generates digital program streams containing programmingmaterial requested by users, e.g., movies requested through a VODservice. In one embodiment, VOD server 119 may generate transportstreams, each comprising one or more program streams. The transportstreams generated by VOD server 119, hereinafter referred to as “VODtransport streams,” are fed to switching unit 117.

Network controller 125, among other tasks, receives requests from usersfor VOD services, and in response, causes VOD server 119 to generate oneor more VOD transport streams containing the requested programmingmaterial. FIG. 4 illustrates a request (denoted 300) sent from an STT,e.g., STT 676, to network controller 125 via an RDC. As shown in FIG. 4,request 300 includes destination field 303 which in this instancecontains the IP (and/or MAC) address of network controller 125 to whichrequest 300 is destined; request data field 306 which contains dataconcerning the requested programming material, e.g., a movie; andorigination field 309 which contains the IP (and/or MAC) address of theSTT from which request 300 originates—in this instance, STT 676.

Under the control of network controller 125, the transport streams fromdigital TV program receiver 109, analog signal processor 111, and VODserver 119 are switched by switching unit 117 to selected modulators inQAM modulator bank 168 in hub 120. The selected modulators modulate therespective transport streams onto various in-band transmission channels,e.g., according to the frequency band allocation illustrated in FIG. 5.In this example, as conventional, band 378 ranging from 650 MHz to 750MHz is allocated for transmission of VOD transport streams, and band 377ranging from 550 MHz to 650 MHz is allocated for transmission of digitalTV transport streams. However, because of the above-described processingby analog signal processor 111 in accordance with the invention, thedigitized analog TV transport streams require only a narrow band(denoted 375) ranging from, say, 150 MHz to 190 MHz, as opposed to priorart analog TV band 103 ranging from 150 MHz to 550 MHz, for transmissionof the same amount of analog TV programming material. As a result, theband ranging from 190 to 550 MHz (denoted 489) which would otherwise beused for transmission of analog programming material in prior art is nowmade available for other use.

In this illustrative embodiment, the “newly available” frequency band489 is utilized to provide additional VOD services to users. FIG. 6 is aflowchart depicting a routine for utilizing band 489 to deliveradditional VOD services. In this embodiment, network controller 125, atstep 520, receives from an STT, e.g., STT 676, a request for VODservices. As an example, suppose that network controller 125 receives aVOD request for the movie, “Roman Holiday.” In response, at step 522,controller 125 directs VOD server 119 to generate a VOD transport streamcontaining a program stream representing the Roman Holiday moviecontent. The VOD transport stream and the program stream are identifiedby a TSID and PID, respectively. The VOD transport stream is switched byswitching unit 117 to QAM modulator bank 168.

At step 525, network controller 125 directs resource manager 166 toallocate bandwidth in network 140 for the VOD transport stream. Tomonitor and allocate bandwidth, resource manager 166 may maintain aresource table such as that shown in FIG. 7. Resource table 590illustratively contains two columns, denoted 592 and 593. Column 592contains an identifier of a transmission channel in the network, e.g.,TC-1. Column 593 contains a TSID identifying a transport stream that iscurrently being transmitted via a respective transmission channel.Referring to row 596, for example, TC-1 is currently utilized totransmit the transport stream identified as TSID 17. A NULL value incolumn 593 indicates that a respective transmission channel is currentlyunused. Referring to row 597, for example, transmission channel TC-3 iscurrently unused.

In accordance with the invention, resource manager 166 may assign anunused transmission channel within band 489 for transmitting theaforementioned VOD transport stream, especially when no transmissionchannels in band 378 are available. Manager 166 informs networkcontroller 125 of such an assignment. By way of example, resourcemanager 166 in this instance assigns transmission channel 376 (shown inFIG. 8A) spanning from 200 MHz to 206 MHz in band 489 for transmittingthe VOD transport stream containing the Roman Holiday movie content.Thus, at step 528, network controller 125 receives from resource manager166 a message indicating the assigned transmission channel 376. Networkcontroller 125 directs switching unit 117 to switch the VOD transportstream to the proper modulator in bank 168 to modulate the VOD transportstream onto assigned transmission channel 376, as indicated at step 530.

Network controller 125 recognizes that the VOD transport streamtransmitted through channel 376 in band 489 needs to befrequency-translated to another band at the user location inanticipation of reoccupation of band 489 by the original, analog TVprogram channel material there, recovered (and decompressed) from thedigitized analog TV transport streams from narrow band 375. Suchrecovery, fully described below, involves gateway 675 performing on thedigitized analog TV transport streams the inverse function to analogsignal processor 111.

To realize the frequency translation of the VOD transport stream,controller 125 at step 532 in this instance assigns a 6 MHz subbandwithin band 378 to which the VOD transport stream is to befrequency-translated at the user location. In this example, networkcontroller 125 assigns subband 678 (illustrated in FIG. 8B) which spansfrom 650 MHz to 656 MHz. To select subband 678, network controller 125considers whether any other VOD transport streams are currentlytransmitted to user location 158-1 through band 378, and selects thesubband such that the frequency-translated VOD transport stream does notinterfere with any such other VOD transport streams to user location158-1.

At step 535, network controller 125 transmits to reception gateway 675 afirst control message, containing data concerning a first carrierfrequency, CF1, of the carrier carrying the VOD transport stream viatransmission channel 376, and a second carrier frequency, CF2, of thecarrier carrying the frequency-translated VOD transport stream throughsubband 678. At step 537, network controller 125 transmits to STT 676 asecond control message, containing data concerning CF2 to which STT 676should tune to receive the appropriate VOD transport stream, and a PIDfor STT 676 to extract therefrom the desired program stream, containingthe Roman Holiday movie content in this instance.

Gateway 675 at user location 158-1 receives from node 150 a compositesignal including respective signals from bands 375, 489, 377 and 378containing analog program channel material, digital program channelmaterial, and VOD programming material. FIG. 8 illustrates gateway 675in accordance with the invention where the composite signal is receivedthrough interface 328. The composite signal is filtered by band-passfilter (BPF) 332 whose passband corresponds to narrow band 375 rangingfrom 150 MHz to 190 MHz in this instance. The output of BPF 332 isdemodulated by QAM demodulators 335, resulting in baseband signalscontaining the digitized analog TV transport streams. MPEG-2 decoder 341performs the inverse function to encoder 220 to decompress the digitizedanalog TV transport streams, resulting in the digitized analog TVprogramming material. Digital-to-analog (D/A) converter 344 performs theinverse function to A/D converter 215 to convert the digitized analog TVprogramming material back to its original analog form. The resultinganalog TV programming material is modulated by QAM modulators 345 ontoanalog TV band 103, to which STT 676 may tune to obtain TV programsattributed to different analog program channels as in prior art.

Gateway controller 380 receives the aforementioned first control messagefrom network controller 125 through an FDC via interface 328. The latterincludes a QPSK demodulator (not shown) for demodulating the controlmessage modulated onto the FDC. As mentioned before, the first controlmessage contains data concerning CF1 and CF2.Based on such data, gatewaycontroller 380 causes tunable BPF 355 to be tuned to CF1 to capture theVOD transport stream in the passband spanning from 200 MHz and 206 MHzin this instance. Controller 380 also causes frequency translator 361 totranslate the output of filter 355 from CF1 to CF2. Translator 361 mayfirst translate the filter output from CF1 to an intermediate frequencybefore ultimately to CF2, which is common. The output of translator 361comprising the VOD transport stream, which occupies subband 678 spanningfrom 650 MHz to 656 MHz in this instance.

BPF 371 filters the composite signal from interface 328 to capture VODtransport streams in band 378 ranging from 650 MHz to 750 MHz. To notinterfere with the frequency-translated VOD transport stream fromtranslator 361, controller 380 causes tunable stop-band filter 375 to betuned to CF2 to block any transport stream from BPF 371 occupying thesame subband 678. Thus, in this instance, filter 375 has a stop-bandspanning from 650 MHz to 656 MHz, corresponding to subband 678.

In addition, BPF 372 filters the composite signal from interface 328 tocapture digital TV transport streams in band 377, ranging from 550 MHzto 750 MHz, to which STT 676 may tune to obtain TV programs attributedto different digital program channels as in prior art. Combiner 364combines the outputs of QAM modulators 346, frequency translator 361,filter 375, and BPF 372, thereby presenting to STT 676 a combined signalcontaining transport streams according to the prior art frequency bandallocation as in FIG. 1.

In particular, the combined signal contains the VOD transport stream insubband 678 which includes therein the program stream representing theRoman Holiday movie content, desired by the user at STT 676. STT 676receives from network controller 125 the aforementioned second controlmessage, as indicated at step 922 in FIG. 10. At step 932, STT 676 tunesto the carrier frequency CF2 identified in the second control message toreceive the VOD transport stream in subband 678. At step 935, STT 676extracts from the transport stream the program stream identified by thePID specified in the second control message. The identified programstream contains the desired VOD program material, i.e., the RomanHoliday movie content. At step 937, STT presents the desired VOD programmaterial to the user by converting the extracted program stream toappropriate signals for the associated TV to play the VOD program.

The foregoing merely illustrates the principles of the invention. Itwill thus be appreciated that those skilled in the art will be able todevise numerous other arrangements which embody the principles of theinvention and are thus within its spirit and scope.

For example, reception gateway 675 and STT 676 at a user location aredisclosed herein as separate devices, it will be appreciated thatgateway 675 may incorporate some or all of the functions of STT 676, orvice versa. Indeed, a person skilled in the art may integrate the twodevices into one.

Further, system 100 and gateway 675 are disclosed herein in a form inwhich various functions are performed by discrete functional blocks.However, any one or more of these functions could equally well beembodied in an arrangement in which the functions of any one or more ofthose blocks or indeed, all of the functions thereof, are realized, forexample, by one or more appropriately programmed processors.

1. A communications apparatus comprising: an interface for receivingfrom a communications network at least first and second signals in afirst frequency band, the first signals containing programming materialand occupying part of the first frequency band; a device for translatingone or more second signals from the first frequency band to a secondfrequency band; and a mechanism for converting the first signals tothird signals, the third signals occupying the first frequency band inits entirety, wherein the third signals contain the same programmingmaterial as the first signals.
 2. The apparatus according to claim 1,wherein the first signals represent digital data concerning theprogramming material.
 3. The apparatus according to claim 2, wherein thethird signals represent the programming material in an analog format. 4.The apparatus according to claim 2, wherein the mechanism includesdecompressing the digital data.
 5. The apparatus according to claim 1,wherein the communications network includes a multi-channel deliverynetwork.
 6. The apparatus according to claim 5, wherein themulti-channel delivery network includes a cable TV network.
 7. Theapparatus according to claim 1, wherein the programming material isattributed to at least one analog TV program channel.
 8. The apparatusaccording to claim 7, wherein the second signals contain programmingmaterial attributed to a source other than the at least one analog TVprogram channel.
 9. The apparatus according to claim 8, wherein thesource provides on-demand programming material.
 10. A system forprocessing at least analog signals representing programming material,transmission of the analog signals requiring first bandwidth of acommunications network, the system comprising: a mechanism forconverting the analog signals to digital data representing theprogramming material, transmission of digital signals which contain thedigital data requiring second bandwidth of the communications network,the second bandwidth being less than the first bandwidth; and aninterface for transmitting the digital signals through a first subbandin a first frequency band of the communications network, the firstfrequency band and the first subband having the first and secondbandwidths, respectively, one or more selected signals being transmittedthrough a second subband in the first frequency band of thecommunications network, the first subband and second subband beingexclusive of each other, the selected signals being translated to asecond frequency band outside the first frequency band after receipt ofthe selected signal from the communications network in anticipation ofrecovering the analog signals from the digital signals after receipt ofthe digital signals from the communications network.
 11. The systemaccording to claim 10, wherein the digital data is compressed.
 12. Thesystem according to claim 10, wherein the communications networkincludes a multi-channel delivery network.
 13. The system according toclaim 12, wherein the multi-channel delivery network includes a cable TVnetwork.
 14. The system according to claim 10, wherein the programmingmaterial is attributed to at least one analog TV program channel. 15.The system according to claim 14, wherein the selected signals containprogramming material attributed to a source other than the at least oneanalog TV program channel.
 16. The system according to claim 15, whereinthe source provides on-demand programming material.
 17. A system forproviding analog program channel material to a device over acommunications network, comprising: a receiver for receiving firstsignals representing the analog program channel material; a processorfor converting the first signals to second signals representing theanalog program channel material, transmission of the second signalsrequiring less bandwidth of the communications network than transmissionof the first signals; and a mechanism for transmitting the secondsignals and one or more selected signal in a first frequency band to thedevice, a message being sent to the device, the message containinginformation concerning a second frequency band to which the selectedsignal is translated after the device receives the selected signals. 18.The system according to claim 17, wherein a second message is sent to aterminal, the second message including information concerning the secondfrequency band from which the selected signal is obtained.
 19. Thesystem according to claim 17, wherein the device includes the terminal.20. The system according to claim 17, wherein the communications networkincludes a multi-channel delivery network.